A 60-70% round trip efficiency would be very impressive for round trip efficiency of electricity to hydrogen and back. Its in the same ballpark as pumped storag

A 60-70% round trip efficiency would be very impressive for round trip efficiency of electricity to hydrogen and back. Its in the same ballpark as pumped storage. I can only assume it's assuming using fuel cells which are 90% efficient for the conversion to electricity. I'm not convinced these have really been deployed at that scale before, the biggest fuel cells I'm aware of are used in non-nuclear submarines where cost is not a priority.